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- Opedal, Øystein H., et al.
(författare)
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Herbivores reduce seedling recruitment in alpine plant communities
- 2021
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 39:2
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Tidskriftsartikel (refereegranskat)abstract
- Through changes in climate and other environmental factors, alpine tundra ecosystems are subject to increased cover of erect shrubs, reduced predictability of rodent dynamics and changes in wild and domesticated herbivore densities. To predict the dynamics of these ecosystems, we need to understand how these simultaneous changes affect alpine vegetation. In the long term, vegetation dynamics may depend critically on seedling recruitment. To study drivers of alpine plant seedling recruitment, we set up a field experiment where we manipulated the opportunity for plant–plant interactions through vegetation removal and introduction of willow transplants, the occurrence of herbivory through caging of plots, and then sowed 14 species into the plots. We replicated the experiment in three common alpine vegetation types (heath, meadow and Salix shrubland) and recorded seedling emergence and survival over five years. Strong effects of vegetation removal and substantial differences in recruitment among dominant vegetation types suggested important effects of local vegetation on the recruitment success of vascular-plant seedlings. Similarly, herbivore exclusion had strong positive effects on recruitment success. This effect arose primarily via reduced seedling mortality in plots from which herbivores had been experimentally excluded and became noticeably stronger over time. In contrast, we detected no consistent effects of experimental willow shrub introduction on seedling recruitment. These results demonstrate that large and small herbivores can affect alpine plant seedling recruitment negatively by trampling and feeding on seedlings. Importantly, the effects became stronger over time, suggesting that effects of herbivory on seedling recruitment accumulates over time and may relate to recruitment phases beyond initial seedling emergence.
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- Vidal-Pineiro, D., et al.
(författare)
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Relationship between cerebrospinal fluid neurodegeneration biomarkers and temporal brain atrophy in cognitively healthy older adults
- 2022
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 116, s. 80-91
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Tidskriftsartikel (refereegranskat)abstract
- It is unclear whether cerebrospinal fluid (CSF) biomarkers of neurodegeneration predict brain atrophy in cognitively healthy older adults, whether these associations can be explained by phosphorylated tau181 (p-tau) and the 42 amino acid form of amyloid-beta (A beta 42) biomarkers, and which neural substrates may drive these associations. We addressed these questions in 2 samples of cognitively healthy older adults who underwent longitudinal structural MRI up to 7 years and had baseline CSF levels of heart-type fatty-acid binding protein (FABP3) = , total-tau, neurogranin, and neurofilament light (NFL) (n = 189, scans = 721). The results showed that NFL, total-tau, and FABP3 predicted entorhinal thinning and hippocampal atrophy. Brain atrophy was not moderated by A beta 42 and the associations between NFL and FABP3 with brain atrophy were independent of p-tau. The spatial pattern of cortical atrophy associated with the biomarkers overlapped with neurogenetic profiles associated with expression in the axonal (total-tau, NFL) and dendritic (neurogranin) components. CSF biomarkers of neurodegeneration are useful for predicting specific features of brain atrophy in older adults, independently of amyloid and tau pathology biomarkers. (C) 2022 The Author(s). Published by Elsevier Inc.
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